The Dow Jones suffered its biggest fall for more than six months amid market jitters about slower worldwide economic growth.

The 318-point fall wiped almost two per cent off the value of shares and reflected concerns about emerging markets.

Over two days the Dow Jones fell by almost 500 points as investors sought to reduce their level of risk by withdrawing from stocks and putting their money in bonds and other comparatively safer assets.

Among the factors to erode confidence in emerging markets was Argentina’s decision to abandon the defence of the peso, prompting an 11 per cent fall in its value against the dollar, and a survey showing China’s manufacturing sector contracted this month.